A critical function of sleep is to allow for memory consolidation. For example, performance on a simple, ixplicit sequence task is improved following a 12 hour interval containing sleep relative to a 12 hour interval without sleep. However, this benefit of sleep is not present in older adults (45-80 years) for sequence earning tasks. Conversely, preliminary research suggests that sleep-dependent memory consolidation may remain intact in older adults for a non-motor, cognitive task (word-pair association learning). These results ead to a number of questions which will be examined in the proposed research. First, does the age-related decline in sleep-dependent memory consolidation of sequence learning tasks reflect changes in sleep architecture with age? Likewise, does the spared sleep benefit on word-pair association learning reflect stability of certain sleep stages? Sleep-related changes in performance on the sequence learning task are associated with NREM-2 sleep while SWS seems to be critical for consolidation of word-pair association learning. Thus, the relationship of memory consolidation and sleep architecture, as measured by polysomnography, will be assessed in individuals ranging from 21-80 years of age. Finally, does sleepindependent memory consolidation of motor learning, off-line changes in performance occurring over a period of time spent awake, also decline in older adults? This question will be addressed with a sequence learning paradigm in which off-line learning can be dissociated into sleep-dependent goal-based learning and sleep-independent movement-based learning